Communication of user specific control information in a wireless network

ABSTRACT

A wireless device generates a High Efficiency Signal B (HE-SIG-B) field by Block Convolution Code (BCC) encoding and rate-matching a BCC block of the HE-SIG-B field, generates a Physical Layer Protocol Data Unit (PPDU) including the HE-SIG-B field, and transmits the PPDU. A total number N is a total number of bits of the HE-SIG-B field that precede the BCC block, and is greater than 0. The BCC block has a puncturing pattern depending on the total number N. A wireless device receives a PPDU. The PPDU includes an HE-SIG-B field that includes an encoded BCC block. The wireless device de-rate-matches the encoded BCC block having a puncturing pattern depending on a total number N. The total number N is a total number of decoded bits of the HE-SIG-B field that preceded the BCC block, and the total number N is greater than 0.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of U.S. Provisional PatentApplication No. 62/252,737, filed Nov. 9, 2015, U.S. Provisional PatentApplication No. 62/263,482, filed Dec. 4, 2015, U.S. Provisional PatentApplication No. 62/269,011, filed Dec. 17, 2015, and U.S. ProvisionalPatent Application No. 62/269,686, filed Dec. 18, 2015, which areincorporated by reference herein in their entireties.

BACKGROUND

1. Technical Field

The technology described herein relates generally to wirelessnetworking. More particularly, the technology relates to thecommunication of user specific control information in a wireless localarea network (WLAN), including coding of the user specific controlinformation.

2. Description of the Related Art

Wireless LAN (WLAN) devices are currently being deployed in diverseenvironments. Some of these environments have large numbers of accesspoints (APs) and non-AP stations in geographically limited areas. Inaddition, WLAN devices are increasingly required to support a variety ofapplications such as video, cloud access, and offloading. In particular,video traffic is expected to be the dominant type of traffic in manyhigh efficiency WLAN deployments. With the real-time requirements ofsome of these applications, WLAN users demand improved performance indelivering their applications, including improved power consumption forbattery-operated devices.

A WLAN is being standardized by the IEEE (Institute of Electrical andElectronics Engineers) Part 11 under the name of “Wireless LAN MediumAccess Control (MAC) and Physical Layer (PHY) Specifications.” A seriesof standards have been adopted as the WLAN evolved, including IEEE Std802.11™-2012 (March 2012) (IEEE 802.11n). The IEEE Std 802.11 wassubsequently amended by IEEE Std 802.11ae™-2012, IEEE Std802.11aa™-2012, IEEE Std 802.11ad™-2012, and IEEE Std 802.11ac™-2013(IEEE 802.11ac).

Recently, an amendment focused on providing a High Efficiency (HE) WLANin high-density scenarios is being developed by the IEEE 802.11ax taskgroup. The 802.11ax amendment focuses on improving metrics that reflectuser experience, such as average per station throughput, the 5thpercentile of per station throughput of a group of stations, and areathroughput. Improvements may be made to support environments such aswireless corporate offices, outdoor hotspots, dense residentialapartments, and stadiums.

A Physical Layer Protocol Data Unit (PPDU) transmitted in an HE WLAN mayinclude user specific control information in an HE Signal B (HE-SIG-B)field. To reduce overhead in the HE WLAN, efficient encoding theinformation in the HE-SIG-B field may be used.

The HE-SIG-B field is encoding using one of a 1/2, 2/3, 3/4, and 5/6coding rate. That is, for each bit in the HE-SIG-B field, an average of2, 1.5, 1.333, or 1.2 bits are encoded for transmission. The bits to beencoded may be generated by producing 2×N bits from N bits of theHE-SIG-B field and then removing some of the 2×N bits. For example, a3/4 bit rate may be generated by generating 6 bits from each 3 bits ofthe HE-SIG-B field and then removing two of each of the generated 6bits, and a 5/6 bit rate may be generated by generating 10 bits fromeach 5 bits of the HE-SIG-B field and then removing four of each of thegenerated 10 bits. This process is known as rate matching, and theremoval of bits may be referred to as puncturing. Generally, thepuncturing is done according to a pattern (a puncturing pattern)determined by the coding rate.

Depending on the coding rate chosen, subfields of the HE-SIG-B field maynot start at boundary used by to perform rate matching.

SUMMARY

In an embodiment, a method performed by a wireless device comprisesgenerating a High Efficiency Signal B (HE-SIG-B) field by BlockConvolution Code (BCC) encoding and rate-matching a BCC block of theHE-SIG-B field, generating a Physical Layer Protocol Data Unit (PPDU)including the HE-SIG-B field, and transmitting the PPDU. A total numberN is a total number of bits of the HE-SIG-B field that precede the BCCblock, the total number N is greater than 0, and the BCC block has apuncturing pattern depending on the total number N.

In an embodiment, the BCC block has a code-rate of K/M, K and M beingpositive integers greater than zero, so that K bits of the BCC block areencoded into M bits. The puncturing pattern depends on a remainder Z.The remainder Z is equal to the total number N modulo K.

In an embodiment, the puncturing pattern is equal to a basic puncturingpattern for the code-rate K/M left cyclic-shifted by the remainder Z.

In an embodiment, BCC encoding the BCC block includes generating a firstset of encoded bits using a first polynomial, and generating a secondset of encoded bits using a second polynomial.

In an embodiment, the code-rate is 3/4, the first set of encoded bitsincludes a first plurality of consecutive three-bit sequences beginningat an earliest bit of the first set, and the second set of encoded bitsincludes a second plurality of consecutive three-bit sequences beginningat an earliest bit of the second set. Rate-matching the BCC blockincludes: i) discarding third bits of each of the first plurality ofconsecutive three-bit sequences and second bits of each of the secondplurality of consecutive three-bit sequences when the remainder Z isequal to zero, ii) discarding second bits of each of the first pluralityof consecutive three-bit sequences of the first set of encoded bits andfirst bits of each of the second plurality of consecutive three-bitsequences when the remainder Z is equal to one, and iii) discardingfirst bits of each of the first plurality of consecutive three-bitsequences and thirds bit of each of the second plurality of consecutivethree-bit sequences when the remainder Z is equal to two.

In an embodiment, the code-rate is 2/3, and the second set of encodedbits includes a plurality of consecutive two-bit sequences beginning atan earliest bit of the second set. Rate-matching the BCC block includes:i) discarding second bits of each of the plurality of consecutivetwo-bit sequences when the remainder Z is equal to zero, and ii)discarding first bits of each of the plurality of consecutive two-bitsequences when the remainder Z is equal to one.

In an embodiment, the code-rate is 5/6, the first set of encoded bitsincludes a first plurality of consecutive five-bit sequences beginningat an earliest bit of the first set, and the second set of encoded bitsincludes a second plurality of consecutive five-bit sequences beginningat an earliest bit of the second set. Rate rate-matching the BCC blockincludes: i) discarding third and fifth bits of each of the firstplurality of consecutive five-bit sequences and second and fourth bitsof each of the second plurality of consecutive five-bit sequences whenthe remainder Z is equal to zero, ii) discarding second and fourth bitsof each of the first plurality of consecutive five-bit sequences andfirst and third bits of each of the second plurality of consecutivefive-bit sequences when the remainder Z is equal to one, iii) discardingfirst and third bits of each of the first plurality of consecutivefive-bit sequences and second and fifth bits of each of the secondplurality of consecutive five-bit sequences when the remainder Z isequal to two, iv) discarding second and fifth bits of each of the firstplurality of consecutive five-bit sequences and first and fourth bits ofeach of the second plurality of consecutive five-bit sequences when theremainder Z is equal to three, and v) discarding first and fourth bitsof each of the first plurality of consecutive five-bit sequences andthird and fifth bits of each of the second plurality of consecutivefive-bit sequences when the remainder Z is equal to four.

In an embodiment, the HE-SIG-B field includes a plurality of BCC blocks,and the method further comprises BCC encoding a plurality of BCC blocksof the HE-SIG-B field as a single codeword.

In an embodiment, the HE-SIG-B field includes a plurality of BCC blocks,and a plurality of total numbers N are respective total numbers of bitsof the HE-SIG-B field that respectively precede the respective BCCblocks of the plurality of BCC blocks. The method further comprisesseparately rate-matching the BCC blocks of the plurality of BCC blocksusing respective puncturing patterns determined using the respectivetotal numbers N.

In an embodiment, the BCC block corresponds to a per-station (per-STA)information field. The per-STA information field includes informationfor one or two stations.

In an embodiment, a method performed by a wireless device comprisesreceiving a Physical Layer Protocol Data Unit (PPDU). The PPDU includesa High Efficiency Signal B (HE-SIG-B) field that includes an encodedBlock Convolution Code (BCC) block. The method further comprisesde-rate-matching the encoded BCC block having a puncturing patterndepending on a total number N. The total number N is a total number ofdecoded bits of the HE-SIG-B field that preceded the BCC block, and thetotal number N is greater than 0.

In an embodiment, the BCC block has a code-rate of K/M, K and M beingpositive integers greater than zero, so that K bits of the BCC block areencoded into M bits, and the puncturing pattern depends on a remainderZ, the remainder Z being equal to the total number N modulo K.

In an embodiment, the puncturing pattern is equal to a basic puncturingpattern for the code-rate K/M left cyclic-shifted by the remainder Z.

In an embodiment, the code-rate is 3/4, and de-rate-matching the encodedBCC block includes, for each of a plurality of consecutive four-valuesequence {x1, x2, x3, x4} in the encoded BCC block: i) generating afirst three-value sequence {x1, x3, D} and a second three-value sequence{x2, D, x4} when the remainder Z is equal to zero; ii) generating thefirst three-value sequence {x1, D, x3} and the second three-valuesequence {D, x2, x4} when the remainder Z is equal to one; and iii)generating the first three-value sequence {D, x2, x4} and the secondthree-value sequence {x1, x3, D} when the remainder Z is equal to two. Dis a predetermined dummy value.

In an embodiment, the code-rate is 2/3, and de-rate-matching the encodedBCC block includes, for each of a plurality of consecutive three-valuesequence {x1, x2, x3} in the encoded BCC block: i) generating a firsttwo-value sequence {x1, x3} and a second two-value sequence {x2, D} whenthe remainder Z is equal to zero; and ii) generating the first two-valuesequence {x1, x2} and the second two-value sequence {D, x3} when theremainder Z is equal to one. D is a predetermined dummy value.

In an embodiment, the code-rate is 5/6, and de-rate-matching the encodedBCC block includes, for each of a plurality of consecutive six-valuesequence {x1, x2, x3, x4, x5, x6} in the encoded BCC block: i)generating a first five-value sequence {x1, x3, D, x6, D} and a secondfive-value sequence {x2, D, x4, D, x6} when the remainder Z is equal tozero; ii) generating the first five-value sequence {x1, D, x3, D, x5}and the second five-value sequence {D, x2, D, x4, x6} when the remainderZ is equal to one; iii) generating the first five-value sequence {D, x2,D, x4, x6} and the second five-value sequence {x1, D, x3, x5, D} whenthe remainder Z is equal to two; iv) generating the first five-valuesequence {x1, D, x3, x5, D} and the second five-value sequence {D, x2,x4, D, x6} when the remainder Z is equal to three; and v) generating thefirst five-value sequence {D, x2, x4, D, x6} and the second five-valuesequence {x1, x3, D, x5, D) when the remainder Z is equal to four. D isa predetermined dummy value.

In an embodiment, the HE-SIG-B field includes a plurality of BCC blocks,and the encoded HE-SIG-B field includes a plurality of portionsrespectively corresponding to the plurality of BCC blocks. The methodfurther comprises de-rate-matching the plurality of portions as a singlecodeword.

In an embodiment, the HE-SIG-B field includes a plurality of BCC blocks,the encoded HE-SIG-B field includes a plurality of portions respectivelycorresponding to the plurality of BCC blocks, and a plurality of totalnumbers N are respective total numbers of bits of the HE-SIG-B fieldthat respectively precede the respective BCC blocks of the plurality ofBCC blocks. The method further comprises separately de-rate-matching theportions of the encoded HE-SIG-B field according to respectivepuncturing patterns determined according to the respective total numbersN.

In an embodiment, the BCC block corresponds to a per-station (per-STA)information field. The per-STA information field includes informationfor one or two stations.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a wireless network, according to an embodiment.

FIG. 2 is a schematic diagram of a wireless device, according to anembodiment.

FIG. 3A illustrates components of a wireless device configured totransmit data, according to an embodiment.

FIG. 3B illustrates components of a wireless device configured toreceive data, according to an embodiment.

FIG. 4A illustrates an HE Physical Layer Protocol Data Unit (PPDU),according to an embodiment.

FIG. 4B shows a Table 1 disclosing additional properties of fields ofthe HE PPDU frame of FIG. 4A, according to an embodiment.

FIG. 5 illustrates an HE-SIG-B field, according to an embodiment.

FIG. 6 illustrates a process for generating combined StationIdentifier/Cyclic Redundancy Check (STA ID/CRC) fields, according to anembodiment.

FIG. 7A illustrates an HE-SIG-B field, according to an embodiment.

FIG. 7B illustrates an HE-SIG-B field, according to another embodiment.

FIG. 8 show a table listing modulation, code-rates, and othercharacteristics for each of a plurality of Modulation and Coding Scheme(MCS) indexes.

FIG. 9 illustrates a process of encoding and decoding at a code-rate of3/4, according to an embodiment.

FIG. 10 illustrates a process of encoding and decoding at a code-rate of2/3, according to an embodiment.

FIG. 11 illustrates a process of encoding and decoding at a code-rate of5/6, according to an embodiment.

FIG. 12 illustrates a process for BCC rate-matching a portion of anHE-SIG-B field, according to an embodiment.

FIG. 13 illustrates patterns for puncturing a rate-matching unit for acode-rate of 3/4 and based on a number of bits preceding therate-matching unit, according to an embodiment.

FIG. 14 illustrates patterns for puncturing a rate-matching unit for acode-rate of 2/3 and based on a number of bits preceding therate-matching unit, according to an embodiment.

FIG. 15 illustrates patterns for puncturing a rate-matching unit for acode-rate of 5/6 and based on a number of bits preceding therate-matching unit, according to an embodiment.

FIG. 16 illustrates a process for encoding and rate-matching an HE-SIG-Bfield using rate-matching based padding, according to an embodiment.

FIG. 17 further illustrates the operation of the process of FIG. 16,according to an embodiment.

FIG. 18 illustrates a process for de-rate-matching and decoding a signalencoded and rate matched using the process of FIG. 16, according to anembodiment.

FIG. 19 illustrates a process for encoding and rate-matching an HE-SIG-Bfield using rate-matching based padding, according to anotherembodiment.

FIG. 20 further illustrates the operation of the process of FIG. 19,according to an embodiment.

FIG. 21 illustrates a process for de-rate-matching and decoding a signalencoded and rate-matched using the process of FIG. 19, according to anembodiment.

FIG. 22A illustrates an HE-SIG-B field including filler bits forrate-matching unit alignment, according to a first embodiment.

FIG. 22B illustrates an HE-SIG-B field including filler bits forrate-matching unit alignment, according to a second embodiment.

DETAILED DESCRIPTION

The technology described herein relates generally to wirelessnetworking. More particularly, the technology relates to techniques forencoding and decoding a High-Efficiency Signal B (HE-SIG-B) field.

In the following detailed description, certain illustrative embodimentshave been illustrated and described. As those skilled in the art wouldrealize, these embodiments are capable of modification in variousdifferent ways without departing from the scope of the presentdisclosure. Accordingly, the drawings and description are to be regardedas illustrative in nature and not restrictive. Like reference numeralsdesignate like elements in the specification.

FIG. 1 illustrates a wireless network according to an embodiment. Thewireless network includes an infrastructure Basic Service Set (BSS) 100of a Wireless Local Area Network (WLAN). In an 802.11 wireless LAN(WLAN), the BSS provides the basic organizational unit and typicallyincludes an Access Point (AP) and one or more associated stations(STAs). In FIG. 1, the BSS 100 includes an Access Point 102 (alsoreferred to as the AP) wirelessly communicating with first, second,third, and fourth wireless devices (or stations) 104, 106, 108, and 110(also referred to as stations STA1, STA2, STA3, and STA4, respectively).The wireless devices may each include a medium access control layer(MAC) and a physical layer (PHY) according to an IEEE 802.11 standard.

Although FIG. 1 shows the BSS 100 including only the first to fourthstations STA1 to STA4, embodiments are not limited thereto and maycomprise BSSs including any number of stations.

The AP 102 is a station, that is, a STA, configured to control andcoordinate functions of the BSS 100. The AP 102 may transmit informationto a single station selected from the plurality of stations STA1 to STA4in the BSS 100 using a single frame, or may simultaneously transmitinformation to two or more of the stations STA1 to STA4 in the BSS 100using either a single Orthogonal Frequency Division Multiplexing (OFDM)broadcast frame, a single OFDM Multi-User Multi-Input-Multi-Output(MU-MIMO) transmission, a single Orthogonal Frequency Division MultipleAccess (OFDMA) frame, or a single MU-MIMO OFDMA frame.

The stations STA1 to STA4 may each transmit data to the AP 102 using asingle frame, or transmit information to and receive information fromeach other using a single frame. Two or more of the stations STA1 toSTA4 may simultaneously transmit data to the AP 102 using an Uplink (UL)OFDMA frame, an UL MU-MIMO frame, or an UL MU-MIMO OFDMA frame.

In another embodiment, the AP 102 may be absent and the stations STA1 toSTA4 may be in an ad-hoc network.

Each of the stations STA1 to STA4 and the AP 102 includes a processorand a transceiver, and may further include a user interface and adisplay device.

The processor is configured to generate a frame to be transmittedthrough a wireless network, to process a frame received through thewireless network, and to execute protocols of the wireless network. Theprocessor may perform some or all of its functions by executing computerprogramming instructions stored on a non-transitory computer-readablemedium.

The transceiver represents a unit functionally connected to theprocessor, and designed to transmit and receive a frame through thewireless network. The transceiver may include a single component thatperforms the functions of transmitting and receiving, or two separatecomponents each performing one of such functions.

The processor and transceiver of the stations STA1 to STA4 and the AP102 may be respectively implemented using hardware components, softwarecomponents, or both.

The AP 102 may be or may include a WLAN router, a stand-alone AccessPoint, a WLAN bridge, a Light-Weight Access Point (LWAP) managed by aWLAN controller, and the like. In addition, a device such as a personalcomputer, tablet computer, or cellular phone may configured able tooperate as the AP 102, such as when a cellular phone is configured tooperate as a wireless “hot spot.”

Each of the stations STA1 to STA4 may be or may include a desktopcomputer, a laptop computer, a tablet PC, a wireless phone, a mobilephone, a smart phone, an e-book reader, a Portable Multimedia Player(PMP), a portable game console, a navigation system, a digital camera, aDigital Multimedia Broadcasting (DMB) player, a digital audio recorder,a digital audio player, a digital picture recorder, a digital pictureplayer, a digital video recorder, a digital video player, and the like.

The present disclosure may be applied to WLAN systems according to IEEE802.11 standards but embodiments are not limited thereto.

In IEEE 802.11 standards, frames exchanged between stations (includingaccess points) are classified into management frames, control frames,and data frames. A management frame may be a frame used for exchangingmanagement information that is not forwarded to a higher layer of acommunication protocol stack. A control frame may be a frame used forcontrolling access to a medium. A data frame may be a frame used fortransmitting data to be forwarded to the higher layer of thecommunication protocol stack.

A type and subtype of a frame may be identified using a type field and asubtype field included in a control field of the frame, as prescribed inthe applicable standard.

FIG. 2 illustrates a schematic block diagram of a wireless device 200according to an embodiment. The wireless or WLAN device 200 may beincluded in the AP 102 or any of the stations STA1 to STA4 in FIG. 1.The WLAN device 200 includes a baseband processor 210, a radio frequency(RF) transceiver 240, an antenna unit 250, a storage device (e.g.,memory) 232, one or more input interfaces 234, and one or more outputinterfaces 236. The baseband processor 210, the memory 232, the inputinterfaces 234, the output interfaces 236, and the RF transceiver 240may communicate with each other via a bus 260.

The baseband processor 210 performs baseband signal processing, andincludes a MAC processor 212 and a PHY processor 222. The basebandprocessor 210 may utilize the memory 232, which may include anon-transitory computer readable medium having software (e.g., computerprogramming instructions) and data stored therein.

In an embodiment, the MAC processor 212 includes a MAC softwareprocessing unit 214 and a MAC hardware processing unit 216. The MACsoftware processing unit 214 may implement a first plurality offunctions of the MAC layer by executing MAC software, which may beincluded in the software stored in the memory 232. The MAC hardwareprocessing unit 216 may implement a second plurality of functions of theMAC layer in special-purpose hardware. However, the MAC processor 212 isnot limited thereto. For example, the MAC processor 212 may beconfigured to perform the first and second plurality of functionsentirely in software or entirely in hardware according to animplementation.

The PHY processor 222 includes a transmitting signal processing unit(SPU) 224 and a receiving SPU 226. The PHY processor 222 implements aplurality of functions of the PHY layer. These functions may beperformed in software, hardware, or a combination thereof according toan implementation.

Functions performed by the transmitting SPU 224 may include one or moreof Forward Error Correction (FEC) encoding, stream parsing into one ormore spatial streams, diversity encoding of the spatial streams into aplurality of space-time streams, spatial mapping of the space-timestreams to transmit chains, inverse Fourier Transform (iFT) computation,Cyclic Prefix (CP) insertion to create a Guard Interval (GI), and thelike. Functions performed by the receiving SPU 226 may include inversesof the functions performed by the transmitting SPU 224, such as GIremoval, Fourier Transform computation, and the like.

The RF transceiver 240 includes an RF transmitter 242 and an RF receiver244. The RF transceiver 240 is configured to transmit first informationreceived from the baseband processor 210 to the WLAN, and provide secondinformation received from the WLAN to the baseband processor 210.

The antenna unit 250 includes one or more antennas. When Multiple-InputMultiple-Output (MIMO) or Multi-User MIMO (MU-MIMO) is used, the antennaunit 250 may include a plurality of antennas. In an embodiment, theantennas in the antenna unit 250 may operate as a beam-formed antennaarray. In an embodiment, the antennas in the antenna unit 250 may bedirectional antennas, which may be fixed or steerable.

The input interfaces 234 receive information from a user, and the outputinterfaces 236 output information to the user. The input interfaces 234may include one or more of a keyboard, keypad, mouse, touchscreen,microphone, and the like. The output interfaces 236 may include one ormore of a display device, touch screen, speaker, and the like.

As described herein, many functions of the WLAN device 200 may beimplemented in either hardware or software. Which functions areimplemented in software and which functions are implemented in hardwarewill vary according to constraints imposed on a design. The constraintsmay include one or more of design cost, manufacturing cost, time tomarket, power consumption, available semiconductor technology, and soon.

As described herein, a wide variety of electronic devices, circuits,firmware, software, and combinations thereof may be used to implementthe functions of the components of the WLAN device 200. Furthermore, theWLAN device 200 may include other components, such as applicationprocessors, storage interfaces, clock generator circuits, power supplycircuits, and the like, which have been omitted in the interest ofbrevity.

FIG. 3A illustrates components of a wireless device configured totransmit data according to an embodiment, including a Transmitting (Tx)SPU (TxSP) 324, an RF transmitter 342, and an antenna 352. In anembodiment, the TxSP 324, the RF transmitter 342, and the antenna 352correspond to the transmitting SPU 224, the RF transmitter 242, and anantenna of the antenna unit 250 of FIG. 2, respectively.

The TxSP 324 includes an encoder 300, an interleaver 302, a mapper 304,an inverse Fourier transformer (IFT) 306, and a guard interval (GI)inserter 308.

The encoder 300 receives and encodes input data DATA. In an embodiment,the encoder 300 includes a forward error correction (FEC) encoder. TheFEC encoder may include a binary convolutional code (BCC) encoderfollowed by a puncturing device. The FEC encoder may include alow-density parity-check (LDPC) encoder.

The TxSP 324 may further include a scrambler for scrambling the inputdata before the encoding is performed by the encoder 300 to reduce theprobability of long sequences of 0s or 1s. When the encoder 300 performsthe BCC encoding, the TxSP 324 may further include an encoder parser fordemultiplexing the scrambled bits among a plurality of BCC encoders. IfLDPC encoding is used in the encoder, the TxSP 324 may not use theencoder parser.

The interleaver 302 interleaves the bits of each stream output from theencoder 300 to change an order of bits therein. The interleaver 302 mayapply the interleaving only when the encoder 300 performs the BCCencoding, and otherwise may output the stream output from the encoder300 without changing the order of the bits therein.

The mapper 304 maps the sequence of bits output from the interleaver 302to constellation points. If the encoder 300 performed LDPC encoding, themapper 304 may also perform LDPC tone mapping in addition to theconstellation mapping.

When the TxSP 324 performs a MIMO or MU-MIMO transmission, the TxSP 324may include a plurality of interleavers 302 and a plurality of mappers304 according to a number of spatial streams (NSS) of the transmission.The TxSP 324 may further include a stream parser for dividing the outputof the encoder 300 into blocks and may respectively send the blocks todifferent interleavers 302 or mappers 304. The TxSP 324 may furtherinclude a space-time block code (STBC) encoder for spreading theconstellation points from the spatial streams into a number ofspace-time streams (NSTS) and a spatial mapper for mapping thespace-time streams to transmit chains. The spatial mapper may use directmapping, spatial expansion, or beamforming.

The IFT 306 converts a block of the constellation points output from themapper 304 (or, when MIMO or MU-MIMO is performed, the spatial mapper)to a time domain block (i.e., a symbol) by using an inverse discreteFourier transform (IDFT) or an inverse fast Fourier transform (IFFT). Ifthe STBC encoder and the spatial mapper are used, the IFT 306 may beprovided for each transmit chain.

When the TxSP 324 performs a MIMO or MU-MIMO transmission, the TxSP 324may insert cyclic shift diversities (CSDs) to prevent unintentionalbeamforming. The TxSP 324 may perform the insertion of the CSD before orafter the IFT 306. The CSD may be specified per transmit chain or may bespecified per space-time stream. Alternatively, the CSD may be appliedas a part of the spatial mapper.

When the TxSP 324 performs a MIMO or MU-MIMO transmission, some blocksbefore the spatial mapper may be provided for each user.

The GI inserter 308 prepends a GI to each symbol produced by the IFT306. Each GI may include a Cyclic Prefix (CP) corresponding to arepeated portion of the end of the symbol that the GI precedes. The TxSP324 may optionally perform windowing to smooth edges of each symbolafter inserting the GI.

The RF transmitter 342 converts the symbols into an RF signal andtransmits the RF signal via the antenna 352. When the TxSP 324 performsa MIMO or MU-MIMO transmission, the GI inserter 308 and the RFtransmitter 342 may be provided for each transmit chain.

FIG. 3B illustrates components of a wireless device configured toreceive data according to an embodiment, including a Receiver (Rx) SPU(RxSP) 326, an RF receiver 344, and an antenna 354. In an embodiment,the RxSP 326, RF receiver 344, and antenna 354 may correspond to thereceiving SPU 226, the RF receiver 244, and an antenna of the antennaunit 250 of FIG. 2, respectively.

The RxSP 326 includes a GI remover 318, a Fourier transformer (FT) 316,a demapper 314, a deinterleaver 312, and a decoder 310.

The RF receiver 344 receives an RF signal via the antenna 354 andconverts the RF signal into symbols. The GI remover 318 removes the GIfrom each of the symbols. When the received transmission is a MIMO orMU-MIMO transmission, the RF receiver 344 and the GI remover 318 may beprovided for each receive chain.

The FT 316 converts each symbol (that is, each time domain block) into afrequency domain block of constellation points by using a discreteFourier transform (DFT) or a fast Fourier transform (FFT). The FT 316may be provided for each receive chain.

When the received transmission is the MIMO or MU-MIMO transmission, theRxSP 326 may include a spatial demapper for converting the respectiveoutputs of the FTs 316 of the receiver chains to constellation points ofa plurality of space-time streams, and an STBC decoder for despreadingthe constellation points from the space-time streams into one or morespatial streams.

The demapper 314 demaps the constellation points output from the FT 316or the STBC decoder to bit streams. If the received transmission wasencoded using the LDPC encoding, the demapper 314 may further performLDPC tone demapping before performing the constellation demapping.

The deinterleaver 312 deinterleaves the bits of each stream output fromthe demapper 314. The deinterleaver 312 may perform the deinterleavingonly when the received transmission was encoded using the BCC encoding,and otherwise may output the stream output by the demapper 314 withoutperforming deinterleaving.

When the received transmission is the MIMO or MU-MIMO transmission, theRxSP 326 may use a plurality of demappers 314 and a plurality ofdeinterleavers 312 corresponding to the number of spatial streams of thetransmission. In this case, the RxSP 326 may further include a streamdeparser for combining the streams output from the deinterleavers 312.

The decoder 310 decodes the streams output from the deinterleaver 312 orthe stream deparser. In an embodiment, the decoder 312 includes an FECdecoder. The FEC decoder may include a BCC decoder or an LDPC decoder.

The RxSP 326 may further include a descrambler for descrambling thedecoded data. When the decoder 310 performs the BCC decoding, the RxSP326 may further include an encoder deparser for multiplexing the datadecoded by a plurality of BCC decoders. When the decoder 310 performsthe LDPC decoding, the RxSP 326 may not use the encoder deparser.

Before making a transmission, wireless devices such as wireless device200 will assess the availability of the wireless medium using ClearChannel Assessment (CCA). If the medium is occupied, CCA may determinethat it is busy, while if the medium is available, CCA determines thatit is idle.

The PHY entity for IEEE Std 802.11 is based on Orthogonal FrequencyDivision Multiplexing (OFDM) or Orthogonal Frequency Division MultipleAccess (OFDMA). In either OFDM or OFDMA Physical (PHY) layers, a STA iscapable of transmitting and receiving Physical Layer Protocol Data Units(PPDUs) that are compliant with the mandatory PHY specifications. A PHYspecification defines a set of Modulation and Coding Schemes (MCS) and amaximum number of spatial streams. Some PHY entities define downlink(DL) and uplink (UL) Multi-User (MU) transmissions having a maximumnumber of space-time streams (STS) per user and employing up to apredetermined total number of STSs.

A PHY entity may define PPDUs that are individually addressed using anAssociation Identifier (AID) or Partial AID and may also define PPDUsthat are group addressed based on Group ID (GID).

A PHY entity may provide support for 20 MHz, 40 MHz, 80 MHz, and 160 MHzcontiguous channel widths and support for an 80+80 MHz non-contiguouschannel width. Each channel includes a plurality of subcarriers, whichmay also be referred to as tones. Data subcarriers within the channelsmay be modulated using binary phase shift keying (BPSK), quadraturephase shift keying (QPSK), 16-quadrature amplitude modulation (16-QAM),64-QAM, and 256-QAM. Forward error correction (FEC) coding (such asconvolutional or Low Density Parity Check (LDPC) coding) may be usedwith coding rates of 1/2, 2/3, 3/4 and 5/6.

A PHY entity may define fields denoted as Legacy Signal (L-SIG), SignalA (SIG-A), and Signal B (SIG-B) within which some necessary informationabout PHY Service Data Unit (PSDU) attributes are communicated. Forexample, a High Efficiency (HE) PHY entity may define an L-SIG field, anHE-SIG-A field, and an HE-SIG-B field. In an embodiment, the symbols inthe L-SIG, SIG-A, and SIG-B fields are encoded with the most robust (andtherefore least efficient) MCS of the PI-TY entity.

To prevent excessive consumption of WLAN resource by overhead, theL-SIG, HE-SIG-A, and HE-SIG-B fields have a limited number of bits andit is advantageous to encode them in the most compact form possible. Ina receiving STA, the symbols of these fields are decoded first in orderto obtain vital information about the PSDU attributes and some MACattributes.

In the IEEE Std 802.11ac, SIG-A and SIG-B fields are called VHT SIG-Aand VHT SIG-B fields. Hereinafter, IEEE Std 802.11ax SIG-A and SIG-Bfields are respectively referred to as HE-SIG-A and HE-SIG-B fields.

FIG. 4A illustrates an HE PPDU 400 according to an embodiment. Atransmitting station generates the HE PPDU frame 400 and transmits it toone or more receiving stations. The receiving stations receive, detect,and process the HE PPDU frame 400.

The HE PPDU frame 400 includes a Legacy Short Training Field (L-STF)field 402, a Legacy (i.e., a Non-High Throughput (Non-HT)) Long TrainingField (L-LTF) 404, a Legacy Signal (L-SIG) field 406, and a RepeatedL-SIG field (RL-SIG) 408, which together comprise a legacy preamble 401.The L-STF 404 of a non-trigger-based PPDU has a periodicity of 0.8 μswith 10 periods.

The HE PPDU frame 400 also includes an HE-SIG-A field 410, an optionalHE-SIG-B field 412, an HE-STF 414, an HE-LTF 416, and an HE-Data field418.

The legacy preamble 401, the HE-SIG-A field 410, and the HE-SIG-B field412 when present, comprise a first part of the HE PPDU frame 400. In anembodiment, the first part of the HE PPDU frame 400 is decoded using a64-element Discrete Fourier Transform (DFT), having a basic subcarrierspacing of 312.5 KHz.

The HE-SIG-A field 410 is duplicated on each 20 MHz segment after thelegacy preamble to indicate common control information. The HE-SIG-Afield 410 includes a plurality of OFDM HE-SIG-A symbols 420 each havinga duration (including a Guard Interval (GI)) of 4 μs. A number of theHE-SIG-A symbols 420 in the HE-SIG-A field 410 is indicated byN_(HESIGA) and is either 2 or 4.

The HE-SIG-B field 412 is included in Down-Link (DL) Multi-User (MU)PPDUs. The HE-SIG-B field 412 includes a plurality of OFDM HE-SIG-Bsymbols 422 each having a duration including a Guard Interval (GI) of 4μs. In embodiments, Single User (SU) PPDUs, Up-Link (UL) MU PPDUs, orboth do not include the HE-SIG-B field 412. A number of the HE-SIG-Bsymbols 422 in the HE-SIG-B field 412 is indicated by N_(HESIGB) and isvariable.

When the HE PPDU 400 has a bandwidth of 40 MHz or more, the HE-SIG-Bfield 412 may be transmitted in first and second HE-SIG-B channels 1 and2. The HE-SIG-B field in the HE-SIG-B channel 1 is referred to as theHE-SIG-B1 field, and the HE-SIG-B field in the HE-SIG-B channel 2 isreferred to as the HE-SIG-B2 field. The HE-SIG-B1 field and theHE-SIG-B2 field are communicated using different 20 MHz bandwidths ofthe HE PPDU 400, and may contain different information. Within thisdocument, the term “HE-SIG-B field” may refer to an HE-SIG-B field of a20 MHz PPDU, or to either of an HE-SIG-B1 field or HE-SIG-B2 field of a40 MHz or more PPDU.

An HE-STF 414 of a non-trigger-based PPDU has a periodicity of 0.8 μswith 5 periods. A non-trigger-based PPDU is a PPDU that is not sent inresponse to a trigger frame. An HE-STF 414 of a trigger-based PPDU has aperiodicity of 1.6 μs with 5 periods. Trigger-based PPDUs include ULPPDUs sent in response to respective trigger frames.

The HE-LTF 416 includes one or more OFDM HE-LTF symbols 426 each havinga duration of 12.8 μs plus a Guard Interval (GI). The HE PPDU frame 400may support a 2×LTF mode and a 4×LTF mode. In the 2×LTF mode, an HE-LTFsymbol 426 excluding a Guard Interval (GI) is equivalent to modulatingevery other tone in an OFDM symbol of 12.8 μs excluding the GI, and thenremoving the second half of the OFDM symbol in a time domain. A numberof the HE-LTF symbols 426 in the HE-LTF field 416 is indicated byN_(HELTF), and is equal to 1, 2, 4, 6, or 8.

The HE-Data field 418 includes one or more OFDM HE-Data symbols 428 eachhaving a duration of 12.8 μs plus a Guard Interval (GI). A number of theHE-Data symbols 428 in the HE-Data field 418 is indicated by N_(DATA)and is variable.

FIG. 4B shows a Table 1 indicating additional properties of the fieldsof the HE PPDU frame 400 of FIG. 4A, according to an embodiment.

The descriptions below, for sake of completeness and brevity, refer toOFDM-based 802.11 technology. Unless otherwise indicated, a stationrefers to a non-AP HE STA, and an AP refers to an HE AP.

FIG. 5 illustrates an HE-SIG-B field 500 according to an embodiment. TheHE-SIG-B field 500 includes a common field 502 and a user-specificinformation field 504.

The common field 502 includes one more Resource Unit (RU) allocationsubfields, in the example here first and second RU allocation subfields510A and 510B. The common field 502 also includes a tail field 512.

The user-specific information field 504 include one or more per-station(per-STA) information fields, in the example here first and secondper-STA information fields 506A and 506B. The user-specific informationfield 504 also includes padding 508.

Each of the per-STA information fields 506A and 506B includes one or twoSTA informations. In the example here, the first per-STA informationfield 506A includes first and second STA informations 514A and 514B, andthe second per-STA information field 506B includes third and fourth STAinformations 514C and 514D. The first and second per-STA informationfields 506A and 506B also include respective tail bits 518A and 518B.

Each of the first to fourth STA informations 514A to 514D include aNumber of Spatial Streams (NSTS) field 522 having 3 bits, a Beamforming(BF) field 5224 of one bit, a Modulation and Coding Scheme (MCS) field526 having four bits, and other information specific to the stations towhich the first to fourth STA informations 514A to 514D are respectivelydirected. In embodiments, the order and size of the fields may differfrom those shown in FIG. 5.

Each of the first to fourth STA informations 514A to 514D also include acombined station identifier (STA ID) and Cyclic Redundancy Check (CRC)(collectively, STA ID/CRC) field 528. The STA ID/CRC field 528 for eachSTA information is created using an identifier, such as an AssociationIdentifier (AID), of the station the STA information is directed to, anda CRC value computed using the remainder of the STA information.

Because the CRC is combined with STA-ID, no extra overhead is incurredby the use of CRC, which improves the efficiency of WLAN channelresource use relative to having separate STA ID and CRC fields. Inaddition, because a separate CRC is used to protect the contents of eachSTA information, errors in one STA information does not propagate toanother STA information.

In an embodiment the STA ID/CRC field 528 is generated by combining aSTA-ID value and a CRC value using a bit-wise exclusive-or (XOR)operation. All or part of the STA-ID value may be XOR'd with the CRCvalue.

FIG. 6 illustrates a process 600 for generating combined STA ID/CRCfields of a per-STA information field 606, according to an embodiment.The per-STA information field 606 includes first and second STAinformations 614A and 614B and a BCC tail field 618.

The first STA information 614A includes first information fields 620A,which may include an NSTS field, a BF field, an MCS field, and so on.The first STA information 614A also includes first STA ID MostSignificant bits (MSb's) field 630A corresponding to most significantbits of a STA ID. The STA ID may be of a station the first STAinformation 614A is directed to, or a STA ID reserved for other uses(e.g. broadcasts).

A first CRC value 634A is computed based on the first information fields620A and the first STA ID MSb's field 630A. A first combined STA ID/CRCfield 628A is generated by bitwise exclusive-or'd the first CRC value634A with Least Significant bits (STA ID LSb's) 632A of the STA ID. Thefirst combined STA ID/CRC field 628A is then included in the first STAinformation 614A.

The second STA information 614B includes second information fields 620B,second STA ID MSb's field 630B, and a second combined STA ID/CRC field628A generated using a second CRC value 634B in the manner described forthe first STA information 614A.

In the embodiment shown in FIG. 6, a bitwidth of a STA ID field islarger than a bitwidth of the CRC value. In another embodiment, abitwidth of a STA ID field is the same as a bitwidth of the CRC value,all of the STA-ID bits are bitwise exclusive-or'd with respective bitsof the CRC value, and none of STA-ID bits are used in calculating theCRC value.

In an embodiment, a CRC generating polynomial for a 4-bit CRC value canbe g(D)=D₄ D+1. In another embodiment, a CRC generating polynomial foran 8-bit CRC value can be g(D)=D₈+D₂+D+1. In another embodiment, a CRCgenerating polynomial for a 16-bit CRC value can be g(D)=D₁₆+D₁₂+D₅+1.

Because the CRC value and part or all of a STA-ID are bitwiseexclusive-or'd, it is beneficial to have same number of bits in the STAID and the CRC value, or to have as many CRC bits as possible withoutexceeding the number of bits in the STA ID. This provides improved CRCprotection while keeping the overall overhead minimal.

FIG. 7A illustrates an HE-SIG-B field 700A, according to a firstembodiment. The HE-SIG-B field 700A includes a common field 702 and auser-specific information field 704A. The user-specific informationfield 704A includes one or more per-STA information fields (in theexample shown, first, second, and third per-STA information fields706A-1, 706A-2, and 706A-3, respectively) and padding 708. The padding708 is used to make the HE-SIG-B field 700A occupy a whole number ofOFDM symbols.

Each of the per-STA information fields 706A-1, 706A-2, and 706A-3includes control information for up to 2 stations: the first per-STAinformation field 706A-1 includes first and second STA informations716-1 and 716-2, the second per-STA information field 706A-2 includesthird and fourth STA informations 716-3 and 716-4, and the third per-STAinformation field 706A-3 includes fifth STA information 716-5. The firstto third per-STA information fields 706A-1, 706A-2, and 706A-3 furtherinclude first to third CRC fields 718-1 to 718-3 and first to third tailbits 720-1 to 720-3, respectively.

The first to fifth STA informations 716-1 to 716-5 may respectivelyinclude control information for first to fifth stations.

The common field 702 includes resource allocation (RU) signaling forvarious bandwidths and can contain up to 4 RU allocation subfields. Theexample of FIG. 7 shows an HE-SIG-B field that is one of two HE-SIG-Bfields (that is, first and second HE-SIG-B channels) in an 80 MHz PPDU,and therefore the common field 702 includes first and second RUallocation fields 710A and 710B, which respectively include RUallocation information for first and second 20 MHz bandwidths of the 80MHz PPDU.

FIG. 7B illustrates an HE-SIG-B field 700B, according to a secondembodiment. The HE-SIG-B field 700B differs from the HE-SIG-B field 700Ain that the first, second, and third per-STA information fields 706B-1,706B-2, and 706B-3 of the user-specific information field 704B do notinclude the CRC fields appended to the one or two STA information ineach of the first, second, and third per-STA information fields 706A-1,706A-2, and 706A-3 of the user-specific information field 704A of FIG.7A.

One of a plurality of modulation and coding schemes (MCS) may be used tomodulate an HE-SIG-B field, depending on device capabilities and channelconditions. The MCS used is generally indicated using an MCS index. FIG.8 show a Table 2 listing modulation and code-rates for each of aplurality of MCS indexes.

A Code-Rate in Table 2 indicates an inverse of a number of bitstransmitted for each bit of data. For example, when data is encodedaccording to an MCS Index of 0, having a code rate of 1/2, 2 bits aretransmitted for each bit of data, and when data is encoded according toan MCS Index of 9, having a code rate of 5/6, 6 bits are transmitted foreach 5 bits of data.

A Modulation in Table 2 indicates a modulation scheme for each carrier.For example, when data is encoded according to an MCS Index of 0, onetransmitted bit is used to modulate each subcarrier, using Binary PhaseShift Keying (BPSK), during each symbol period, and when data is encodedaccording to an MCS Index of 9, 8 transmitted bits are used to modulateeach subcarrier, using a 256-point-constellation Quadrature AmplitudeModulation (256-QAM), during each symbol period. Other modulationschemes that may be used are Quadrature Phase Shift Keying (QPSK) andQAM with other constellation sizes, as shown in Table 2.

Table 2 also shows a rate-matching unit, that is, a number of bits (orbit pairs) that may be grouped together when performing rate matching,for each MCS Index. For example, when data is encoded according to anMCS Index of 0, rate matching is performed on individual bits(transforming each bit into two bits), and when data is encodedaccording to an MCS Index of 9, rate matching is performed on groups of5 bits (transforming each group of 5 bits into 6 bits).

Table 2 also shows a number of subcarriers per OFDM symbol (N_(SD)) inan HE-SIG-B field. From this, a number of encoded (post-rate-matching)bits per OFDM symbol N_(CBPS) can be computed as the product of thenumber of bits used to modulate each subcarrier during each symbolperiod and the number of subcarriers. For example, when data is encodedaccording to an MCS Index of 0, each 52-subcarrier OFDM symbol includes52 encoded bits and N_(CBPS)=52, and when data is encoded according toan MCS Index of 9, each 52-subcarrier OFDM symbol includes 416 encodedbits and N_(CBPS)=416.

From the Code-Rate and the number of encoded bits per OFDM symbolN_(CBPS), a number of payload bits per OFDM symbol N_(DBPS) can bedetermined. For example, when data is encoded according to an MCS Indexof 0, each 52-subcarrier OFDM symbol includes 26 payload bits (half thenumber of encoded bits) and N_(DBPS)=26, and when data is encodedaccording to an MCS Index of 9, each 52-subcarrier OFDM symbol includesfloor (416×5/6)=346 encoded bits and N_(DBPS)=346.

In some WLAN transmissions, information is structured such that BCCencoded signals after rate matching are generated in units of OFDMsymbols. Accordingly, a number of bits in the padding field of anHE-SIG-B field may be adjusted so that the HE-SIG-B field has a lengthequal to an integer multiple of the number of payload bits per OFDMsymbol N_(DBPS) for the MCS used to transmit the HE-SIG-B field. Forexample, referring to Table 2, if the HE-SIG-B field is to betransmitted according to an MCS Index of 6 (3/4 Code-Rate, 64-QAM),padding may be added to the HE-SIG-B field to produce a padded length ofthe HE-SIG-B field that is an integer multiple of 234 bits.

For implementation reasons, a receiver may be designed to decode thecommon field and the per-STA information field(s) of an HE-SIG-B fieldseparately. However, in an embodiment, a size of the common field and asize of the per-STA information field(s) are not designed to enablerate-matching in a manner that allows separate decoding of the commonand the per-STA information field in a straight-forward manner.

FIGS. 9, 10, and 11 illustrate processes for encoding and decoding atcode-rates of 3/4, 2/3, and 5/6, respectively, using puncturing.

FIG. 9 illustrates a process 900 of encoding and decoding at a code-rateof 3/4, according to an embodiment. Rate matching for binaryconvolutional code (BCC) is adapting the code-rate for a given payloadby puncturing the 1/2 code-rate (i.e. mother code-rate) encoded bits.

In a transmitter 902, at S905 a payload 904 is encoded at a “mothercode-rate” of 1/2 using a pair of polynomials. A first set of encodedbits 906-1 having a same length as the payload 904 is generated by aconvolution encoder using a first generator polynomial. A second set ofencoded bits 906-2 having a same length as the payload 904 is generatedby a convolution encoder using a second generator polynomial. Bits inthe first set of encoded bits 906-1 are indicated as A0, A1, A2, and soon, with A0 the earliest bit in the first set of encoded bits 906-1.Bits in the second set of encoded bits 906-2 are indicated as B0, B1,B2, and so on, with B0 the earliest bit in the second set of encodedbits 906-2.

In an embodiment, the first generator polynomial g0=133₈ and the secondgenerator polynomial g1=171₈. Accordingly, for a value t, a bit A_(t) inthe first set of encoded bits 906-1 is equal toX_(t)+X_(t-2)+X_(t-3)+X_(t-5)+X_(t-6), and a bit B_(t) in the first setof encoded bits 906-2 is equal to X_(t)+X_(t-1)+X_(t-2)+X_(t-3)+X_(t-6).

At S907, the first and second sets of encoded bits 906-1 and 906-2 arepunctured to generate first and second sets of punctured encoded bits908-1 and 908-2. In each triplet of paired A and B bits, the third A bitand the second B bits are omitted. For example, in the triplet of bitpairs {{A0, B0), {A1, B1}, {A2, B2}}, bits A2 and B1 are omitted,leaving 4 bits. In the triplet of bit pairs {{A3, B3), {A4, B4}, {A5,B5}}, bits A5 and B4 are omitted. The omitted bits may be referred to asstolen bits.

At S909, the first and second punctured encoded bits 908-1 and 908-2 aretransmitted in sequence as a punctured encoded bit stream 910. In thepunctured encoded bit stream 910, bits of the first set of puncturedencoded bits 908-1 are output before corresponding bits of the secondset of punctured encoded bits 908-2, for example, A0 is output beforeB0. A0 is the earliest bit of the punctured encoded bit stream 910, andcorresponds to an earliest value of the punctured encoded bit stream 910as received by a receiver 912.

In the receiver 912, at S911, the punctured encoded bit stream 910 isreceived, separated into two sets of value, and dummy values (indicatedby shading) are inserted into the two sets of values at the locations ofthe stolen bits to produce first and second sets of received encodedvalues 914-1 and 914-2. The distribution of bits in the puncturedencoded bit stream 910 to the two sets of values and the locations atwhich dummy bits are inserted are determined by the puncturing patternused in S907. In an embodiment, the dummy bits have a value of zero.

At S913, the first and second sets of received encoded bits 914-1 and914-2 are decoded to produce the received bits 916. In an embodiment,the first and second sets of received encoded values 914-1 and 914-2 aredecoded using a Viterbi decoder.

FIG. 10 illustrates a process 1000 of encoding and decoding at acode-rate of 2/3, according to an embodiment.

In a transmitter 1002, at S1005 a payload 1004 is encoded at a code-rateof 1/2 using a pair of polynomials to produce first and second sets ofencoded bits 1006-1 and 1006-2, as described above for the first andsecond sets of encoded bits 906-1 and 906-2 of FIG. 9. Bits in the firstset of encoded bits 1006-1 are indicated as A0, A1, A2, and so on. Bitsin the second set of encoded bits 1006-2 are indicated as B0, B1, B2,and so on.

At S1007, the first and second sets of encoded bits 1006-1 and 1006-2are punctured to generate first and second sets of punctured encodedbits 1008-1 and 1008-2. In each pair of paired A and B bits, the secondB bit is omitted. For example, in the pair of bit pairs {{A0, B0), {A1,B1}}, bit B1 is omitted, leaving 3 bits. In the pair of bit pairs {{A2,B2), {A3, B3}}, bit B3 are omitted.

At S1009, the first and second punctured encoded bits 1008-1 and 1008-2are transmitted in sequence as a punctured encoded bit stream 1010. Inthe punctured encoded bit stream 1010, bits of the first set ofpunctured encoded bits 1008-1 are output before corresponding bits ofthe second set of punctured encoded bits 1008-2, for example, A0 isoutput before B0.

In a receiver 1012, at S1011, the punctured encoded bit stream 1010 isreceived, distributed into two sets of values, and dummy bits (indicatedby shading) are inserted at the locations of the stolen bits to producefirst and second sets of received encoded values 1012-1 and 1012-2. Thedistribution of bits in the punctured encoded bit stream 1010 to the twosets of values and the locations at which dummy bits are inserted aredetermined by the puncturing pattern used in S1007. In an embodiment,the dummy bits have a value of zero.

At S1013, the first and second sets of received encoded values 1012-1and 1012-2 are decoded to produce the received bits 1014. In anembodiment, the first and second sets of received encoded values 1012-1and 1012-2 are decoded using a Viterbi decoder.

FIG. 11 illustrates a process 1100 of encoding and decoding at acode-rate of 5/6, according to an embodiment.

In a transmitter 1102, at S1105 a payload 1104 is encoded at a code-rateof 1/2 using a pair of polynomials to produce first and second sets ofencoded bits 1106-1 and 1106-2, as described above for the first andsecond sets of encoded bits 906-1 and 906-2 of FIG. 9. Bits in the firstset of encoded bits 1106-1 are indicated as A0, A1, A2, and so on. Bitsin the second set of encoded bits 1106-2 are indicated as B0, B1, B2,and so on.

At S1107, the first and second sets of encoded bits 1106-1 and 1106-2are then punctured to generate first and second sets of puncturedencoded bits 1108-1 and 1108-2. In each quintuplet of paired A and Bbits, the second B bit, third A bit, fourth B bit, and fifth A bit areomitted. For example, in the quintuplet of bit pairs {{A0, B0), {A1,B1}, {A2, B2}, {A3, B3}, {A4, B4}}, bits B1, A2, B3, and A4 are omitted,leaving 6 bits.

At S1109, the first and second punctured encoded bits 1108-1 and 1108-2are transmitted in sequence as a punctured encoded bit stream 1110. Inthe punctured encoded bit stream 1110, bits of the first set ofpunctured encoded bits 1108-1 are output before corresponding bits ofthe second set of punctured encoded bits 1108-2, for example, A0 isoutput before B0.

In a receiver 1112, at S1111, the punctured encoded bit stream 1110 isreceived distributed into two sets of values, and dummy bits (indicatedby shading) are inserted at the locations of the stolen bits to producefirst and second sets of received encoded bits 1112-1 and 1112-2. Thedistribution of bits in the punctured encoded bit stream 1110 to the twosets of values and the locations at which dummy bits are inserted aredetermined by the puncturing pattern used in S1107. In an embodiment,the dummy bits have a value of zero.

At S1113, the first and second sets of received encoded bits 1112-1 and1112-2 are decoded to produce the received bits 1114. In an embodiment,the first and second sets of received encoded bits 1112-1 and 1112-2 aredecoded using a Viterbi decoder.

As shown above, rate-matching for BCC is performed in units of 1, 2, 3,or 5 bits, depending on which code-rate is used. For 1/2 code-ratetransmission, no rate-matching needs to be performed. For 2/3 code-ratetransmission, information bits are taken in units of 2 for rate-matchingpurposes, that is, the rate-matching unit is 2 bits. For 3/4 code-ratetransmission, the rate-matching unit is 3 bits. For 5/6 code-ratetransmission, rate-matching unit is 5 bits.

When a code-rate of 2/3, 3/4, or 5/6 is used and a common field or aper-STA information field of an HE-SIG-B field does not have a lengththat is an integer multiple of 2, 3, or 5, respectively, how to applyrate-matching for the content of the HE-SIG-B field must be determined.

FIG. 12 illustrates a process 1200 for BCC rate-matching of a portion ofan HE-SIG-B field 1202, according to an embodiment. The processor may beperformed by a device in a WLAN performing a transmission, such as anAP. In the example provided, the code-rate is 3/4 with rate-matchingunit of 3 bits, but embodiments are not limited thereto.

The HE-SIG-B field 1202 includes a first information field 1204-1 whichis one of a common field or a per-STA information field, and a secondinformation field 1204-2 which is a per-STA information field. TheHE-SIG-B field 1202 may also include addition information fields, whichmay be per-STA information fields. In the embodiment, each of the commonfield or per-STA information fields included in the HE-SIG-B field 1202are treated as a separate BCC encoding and rate-matching block(hereinafter, BCC block). Accordingly, each of the fields includes a6-bit tail at the end of the field, such as the 6 tail bits 1204-1-Tshown included in the first information field 1204-1-T.

In the embodiment of FIG. 12, rate-matching is performed as ifinformation in the HE-SIG-B field was a single codeword. Therefore, theHE-SIG-B field includes a plurality of consecutive 3-bit rate-matchingunits 1202-1, 1202-2, . . . , 1202-12, and so on. In the example, thefirst information field 1204-1 has a length of 31 bits that is not amultiple of the rate-matching unit, but embodiments are not limitedthereto. In contrast, in previously known 802.11 systems, BCC blocks aredesigned to have lengths equal to an integer multiple of therate-matching units that might be used to encode the of BCC block.

Therefore, in the embodiment, wherein i) the BCC blocks are not always amultiple of the rate-matching unit, and ii) the end result is to be thesame as if the rate matching was performed on the HE-SIG-B field as asingle codeword, a puncturing pattern used for an BCC block in theHE-SIG-B field may vary depending on the location of the BCC block, andin particular may be based on a number of bits preceding the BCC blockin the HE-SIG-B field.

At S1205, the HE-SIG-B field 1202 is encoded at a “mother code-rate” of1/2 using a pair of polynomials to produce first and second sets ofencoded bits 1206-1 and 1206-2, as described above for the first andsecond sets of encoded bits 906-1 and 906-2 of FIG. 9. Bits in the firstset of encoded bits 1206-1 are indicated as A0, A1, A2, and so on. Bitsin the second set of encoded bits 1206-2 are indicated as B0, B1, B2,and so on. In an embodiment, each of the information fields 1204-1 and1204-2 are separately encoded at the mother code-rate.

The first information field 1204-1 is encoded to form a first portion1208-1 of the first and second sets of encoded bits 1206-1 and 1206-2.The second information field 1204-2 is encoded to form a second portion1208-2 of the first and second sets of encoded bits 1206-1 and 1206-2.

At S1209, the first and second sets of encoded bits 1206-1 and 1206-2are punctured to generate first and second sets of punctured encodedbits 1210-1 and 1210-2.

In each triplet of paired A and B bits for the first portion 1208-1 ofthe first and second sets of encoded bits 1206-1 and 1206-2,corresponding to the first through tenth rate-matching units 1201-1 to1201-10 and a portion of the rate-matching units 1201-11, the third Abit and the second B bits are omitted. For example, in the triplet ofbit pairs {{A0, B0), {A1, B1}, {A2, B2}} corresponding to the firstrate-matching unit 1201-1, the third A bit (A2) and the second B bit(B1) are omitted, leaving 4 bits, and in the triplet of bit pairs {{A3,B3), {A4, B4}, {A5, B5}}, corresponding to the second rate-matching unit1201-2, the third A bit (A5) and the second B bit (B4) are omitted,leaving 4 bits. The omitted bits may be referred to as stolen bits.

In the embodiment, the transmitted bit stream 1214 produced by theprocess 1200 is identical to what would be produced if the HE-SIG-Bfield 1202 were punctured using a same puncturing pattern for each therate-matching units 1201-1, 1201-2, . . . 1201-12, and so on. However,when the second information field 1204-2 is encoded separately from thefirst information field 1204-1, the second information 1204-2 may beencoded and punctured using offset rate-matching units 1203-1, 1203-2,and so on. As a result, the puncturing pattern used for the offsetrate-matching units 1203-1, 1203-2, and so on may be different from thepuncturing pattern used for the first to tenth rate matching units1201-1 to 1201-10.

As can be seen in FIG. 12, the pattern used to puncture the offsetrate-matching units 1203-1, 1203-2, and so on of second portion 1208-2of the first and second sets of encoded bits 1206-1 and 1206-2,corresponding to the second field 1204-2 (hereinafter, the offsetpattern) is equivalent to a bit-wise rotation of the pattern used topuncture the mother-rate encoded bits of the first and rate-matchingunits 1201-1, 1203-2, and so on. The amount of the bit-wise rotation isdetermined by the number of bits remaining after the last completerate-matching unit to occur before the second field 1204-2. A number ofsuch bits remaining Z is equal to:Z=N modulo K  Equation 1wherein N is the number of bits in the HE-SIG-B field that precede thesecond field 1204-2 and K is the size (N_(RM)) of the rate-matchingunits in bits.

In the example of FIG. 12, N equals 31, K equals 3, and Z is equal to 1(indicating that only 1 bit, X30, remains after the last completerate-matching unit preceding the second field 1204-2. As a result, theoffset pattern used to puncture the first offset rate-matching unit1203-1 of the BCC block including the second information field 1204-2 isequal to the pattern used to puncture the rate-matching units 1201-1,1202-2, etcetera, cyclically rotated Z bits to the left (here, 1).

Therefore, in the triplet of bit pairs {{A31, B31), {A32, B32}, {A33,B33}} that comprise the encoded bits of the first offset rate-matchingunit 1203-1, the second A bit (A32) and the first B bit (B31) aredeleted, instead of the third A bits and the second B bit as was thecase in the rate-matching units 1201-1, 1202-2, etcetera.

At S1213, the first and second punctured encoded bits 1210-1 and 1210-2are sent for transmission in a sequence as a punctured encoded bitstream 1214. In the punctured encoded bit stream 1214, bits of the firstset of punctured encoded bits 1210-1 are ordered before correspondingbits of the second set of punctured encoded bits 1210-2, for example, A0is ordered before B0.

FIG. 13 illustrates patterns for puncturing first and secondrate-matching units 1303-1 and 1303-2 for a code-rate of 3/4 based on anumber of bits preceding the rate-matching unit, according to anembodiment.

A first puncturing pattern 1300A is used when, for N equal to a numberof bits in the HE-SIG-B field that precede the rate-matching unit and Kbeing the size of the rate-matching unit (here, 3), N modulo K(represented by Z) is equal to zero. When the first puncturing pattern1300A is used, the respective third A and second B bits of therate-matching units 1303-1 and 1303-2 are discarded.

A second puncturing pattern 1300B is used when Z is equal to one. Whenthe second puncturing pattern 1300B is used, the respective second A andfirst B bits of the rate-matching units 1303-1 and 1303-2 are discarded.

A third puncturing pattern 1300C is used when Z is equal to two. Whenthe third puncturing pattern 1300C is used, the respective first A andthird B bits of the rate-matching units 1303-1 and 1303-2 are discarded.

FIG. 14 illustrates patterns for puncturing first and secondrate-matching units 1403-1 and 1403-2 for a code-rate of 2/3 based on anumber of bits preceding the rate-matching unit, according to anembodiment.

A first puncturing pattern 1400A is used when, for N equal to a numberof bits in the HE-SIG-B field that precede the rate-matching unit and Kbeing the size of the rate-matching unit (here, 2), N modulo K(represented by Z) is equal to zero. When the first puncturing pattern1400A is used, the respective second B bits of the rate-matching units1403-1 and 1403-2 are discarded.

A second puncturing pattern 1400B is used when Z is equal to one. Whenthe second puncturing pattern 1400B is used, the respective first B bitsof the rate-matching units 1403-1 and 1403-2 are discarded.

FIG. 15 illustrates patterns for puncturing first and secondrate-matching units 1503-1 and 1503-2 for a code-rate of 5/6 based on anumber of bits preceding the rate-matching unit, according to anembodiment.

A first puncturing pattern 1500A is used when, for N equal to a numberof bits in the HE-SIG-B field that precede a rate-matching unit and Kbeing the size of the rate-matching unit (here, 5), N modulo K(represented by Z) is equal to zero. When the first puncturing pattern1500A is used, the respective third A, fifth A, second B, and fourth Bbits of the rate-matching units 1503-1 and 1503-2 are discarded.

A second puncturing pattern 1500B is used when Z is equal to one. Whenthe second puncturing pattern 1500B is used, the respective second A,fourth A, first B, and third BB bits of the rate-matching units 1503-1and 1503-2 are discarded.

A third puncturing pattern 1500C is used when Z is equal to two. Whenthe third puncturing pattern 1500C is used, the respective first A,third A, second B, and fifth B bits of the rate-matching units 1503-1and 1503-2 are discarded.

A fourth puncturing pattern 1500D is used when Z is equal to three. Whenthe fourth puncturing pattern 1500D is used, the respective second A,fifth A, first B, and fourth B bits of the rate-matching units 1503-1and 1503-2 are discarded.

A fifth puncturing pattern 1500E is used when Z is equal to four. Whenthe fifth puncturing pattern 1500E is used, the respective first A,fourth A, third B, and fifth B bits of the rate-matching units 1503-1and 1503-2 are discarded.

In an embodiment wherein a receiver processes each information field ina received HE-SIG-B field as a separate BCC block, the receiver mustidentify the rate-matching pattern for each information field and applya corresponding de-rate-matching and decoding algorithms for each BCCblock, according to the number of bits before each BCC block in theHE-SIG-B field before it was encoded.

In other embodiments, filler bits are inserted after each informationfield in an HE-SIG-B field so that each BCC block starts at arate-matching unit boundary, that is, so that each information fieldcorresponding to a BCC block (that is, a common field and each of one ormore per-STA information fields) in the HE-SIG-B field has a lengthequal to an integer multiple of the rate-matching unit size K (K beingone of 1, 2, 3 and 5) for the MCS being used to encode the HE-SIG-Bfield.

For example, when a length of a common field of an HE-SIG-B field is 18and a rate-matching unit size K is equal to 5, then 2, 7 or, for somepositive integer n, n×K+2 filler bits may be appended to the commonfield to make the common field an integer multiple of K bits long.

FIG. 16 illustrates a process 1600 for encoding and rate-matching anHE-SIG-B field 1602 using rate-matching based padding, according to anembodiment. The HE-SIG-B field 1602 includes a common field 1610 and oneor more per-STA information fields 1614. Each per-STA information field1614 includes information for one or two stations.

At S1603A, the process 1600 appends padding bits 1616A to the commonfield 1610 to generate a padded common field 1610P. A length of thepadding bits 1616A is selected to produce the padded common field 1610Phaving a length equal to an integer multiple of the rate-matching unitcorresponding to an MCS being used to encode and rate-match the HE-SIG-Bfield 1602.

At S1603B, the process 1600 appends padding bits 1616B to the per-STAinformation fields 1614 to generate a padded per-STA information fields1614P. A length of the padding bits 1616A is selected to produce thepadded common field 1610P having a length equal to an integer multipleof the rate-matching unit corresponding to the MCS.

In an embodiment of the process 1600, the padding bits 1616A and 1616Bmay inserted anywhere within the common field 1610 and each of theuser-specific information fields 1614, instead of being at the end, andneed not be contiguous.

At S1605A and S1605B, the padded common field 1610P and the paddedper-STA information fields 1614P are respectively encoded at the mothercode-rate of 1/2. At S1607A and S1607B, the encoded padded common field1610P and the encoded padded per-STA information fields 1614P arerespectively rate-matched using a puncturing pattern corresponding tothe MCS.

The puncturing pattern is not dependent of the respective locations ofthe common field 1610 and or the per-STA information fields 1614 withinthe HE-SIG-B field 1602. Accordingly, each of the common field 1610 andthe one or more per-STA information fields 1614 will have berate-matched using an identical puncturing pattern and are each boundaryaligned with the rate-matching units of the transmission.

At S1609, the encoded rate-matched padded common field 1610P and the oneor more encoded rate-matched padded per-STA information fields 1614P areconcatenated and frequency interleaved in units of the OFDM symbol. Thatis, blocks of the combined encoded rate-matched padded common field1610P and the one or more encoded rate-matched padded per-STAinformation fields 1614P, each blocks having a length equal to thenumber of bits in the OFDM symbol N_(CBPS) for the MCS, are interleavedamong subcarriers of the OFDM symbol.

At S1611, the output of the interleaving process S1609 is modulatedusing an inverse Fourier Transform (iFT), such as an inverse FastFourier Transform (iFFT). The output of the modulation process S1611 isthen transmitted.

FIG. 17 illustrates a process 1700 for BCC rate-matching of a portion ofan HE-SIG-B field 1702, according to the embodiment of FIG. 16. Theprocess 1700 may be performed by a device in a WLAN performing atransmission, such as an AP. In FIG. 17, the code-rate is 3/4 and therate-matching unit is therefore 3 bits, but embodiments are not limitedthereto.

The HE-SIG-B field 1702 includes a first information field 1704-1 whichis one of a common field or a per-STA information field, and a secondinformation field 1704-2 which is a per-STA information field. TheHE-SIG-B field 1702 may also include addition information fields, whichwould be per-STA information fields. In the embodiment, each of thecommon field or per-STA information fields included in the HE-SIG-Bfield 1702 are treated as a separate BCC encoding and rate-matchingblock (hereinafter, BCC block). Accordingly, each of the informationfields includes a 6-bit tail at the end of the field, such as the 6 tailbits 1704-1-T shown included in the first field 1704-1-T.

In the embodiment of FIG. 17, rate-matching is performed independentlyfor each of information fields 1704-1 and 1704-2. Therefore, theHE-SIG-B field includes a plurality of consecutive 3-bit rate-matchingunits 1702-1, 1702-2, . . . , 1702-12, and so on.

In the example, the first information field 1704-1 has an unpaddedlength of 31 bits that is not a multiple of the rate-matching unit, butembodiments are not limited thereto. In contrast, in previously known802.11 systems, information fields that were to be BCC encoded and ratematched as a unit are designed to have lengths equal to an integermultiple of the rate-matching units that might be used to encode the ofinformation field.

Therefore, in the embodiment, wherein rate-matching is performedseparately for separate information fields within the HE-SIG-B field,each information fields is padded to be a multiple of the rate-matchingunit. In the example of FIG. 17, the first information field 1704-1 ispadded with padding bits 1704-1-P, which adds two bits to the length ofthe first information field 1704-1. As a result, the first informationfield 1704-1 has a length of 33, which is an integer number of therate-matching units 1702-1, 1702-2, and so on.

At S1705, the first and second information fields 1704-1 and 1704-2,after padding, are each encoded at a “mother code-rate” of 1/2 using apair of polynomials to produce first and second sets of encoded bits1706-1 and 1706-2, as described above for the first and second sets ofencoded bits 906-1 and 906-2 of FIG. 9. Bits in the first set of encodedbits 1706-1 are indicated as A0, A1, A2, and so on. Bits in the secondset of encoded bits 1706-2 are indicated as B0, B1, B2, and so on.

The first information field 1704-1, including padding bits 1704-1-P, isencoded to form a first portion 1708-1 of the first and second sets ofencoded bits 1706-1 and 1706-2. The second information field 1704-2 isencoded to form a second portion 1708-1 of the first and second sets ofencoded bits 1706-1 and 1706-2.

At S1709, the first and second sets of encoded bits 1706-1 and 1706-2are punctured to generate first and second sets of punctured encodedbits 1710-1 and 1710-2.

In each consecutive triplet of paired A and B bits of the first andsecond sets of encoded bits 1706-1 and 1706-2 (each triplet of pairedbits corresponding to a rate-matching unit) the third A bit and thesecond B bits are discarded. For example, in the triplet of bit pairs{{A0, B0), {A1, B1}, {A2, B2}} corresponding to the first rate-matchingunit 1701-1, the third A bit (A2) and the second B bit (B1) are omitted,leaving 4 bits; in the triplet of bit pairs {{A30, B30), {A31, B31},{A32, B32}}, corresponding to the eleventh rate-matching unit 1701-11,the third A bit (A32) and the second B bit (B31) are omitted, leaving 4bits; and in the triplet of bit pairs {{A33, B33), {A34, B34}, {A35,B35}}, corresponding to the twelfth rate-matching unit 1701-12, thethird A bit (A35) and the second B bit (B32) are omitted, leaving 4bits. The discarded bits may be referred to as stolen bits.

At S1713, the first and second punctured encoded bits 1710-1 and 1710-2are transmitted in sequence as a punctured encoded bit stream 1714. Thepunctured encoded bit stream 1714 includes a first portion 1716-1corresponding to the first field 1704-1 and the padding 1704-1-P, and asecond portion 1716-2 corresponding to the second field 1704-2 and anypadding that it might have appended to it. In the punctured encoded bitstream 1714, bits of the first set of punctured encoded bits 1710-1 areordered before corresponding bits of the second set of punctured encodedbits 1710-2, for example, A0 is ordered before B0.

FIG. 18 illustrates a process 1800 for decoding a received HE-SIG-Bsignal 1802, according to an embodiment. The process 1800 is suitablefor use by a wireless device to decode a transmission performedaccording to the process 1600 of FIG. 16.

As S1803, the received HE-SIG-B signal 1802 is demodulated and equalizedto produce a demodulated and equalized received HE-SIG-B signal. Theequalization may include phase tracking and compensation. Thedemodulation may output signals in the form of log-likelihood ratio(LLR) values.

At S1805, the demodulated and equalized received HE-SIG-B signal isde-interleaved in units of OFDM signals to generate a demodulatedreceived HE-SIG-B signal 1804. When the demodulation of S1803 outputssignals in the form of LLR values, the LLR values are de-interleaved inunits of OFDM symbols to generate the demodulated received HE-SIG-Bsignal 1804 and then sent for de-rate mapping at S1807.

At S1807, the demodulated received HE-SIG-B signal 1804 is divided intoblocks, and each block is de-rate-mapped. De-rate mapping includesinserting dummy bits to replace bits discarded during a rate mappingperformed at, for example, S1607A or S1607B of FIG. 16. The ordering ofthe values of the demodulated received HE-SIG-B signal 1804 and thedummy bits is determined by the puncturing pattern used during the ratemapping.

At S1809, the de-rate-mapped blocks are each decoded to produce a commonfield 1810 and one or more per-STA information fields 1814. A Viterbialgorithm may be used to perform the decoding.

At S1811, the CRC and BCC tail bits, and any filler bits added at, forexample, S1603 or S1603B of FIG. 16, are removed from the common field1810 and one or more per-STA information fields 1814.

FIG. 19 illustrates a process 1900 for encoding and rate-matching aHE-SIG-B field 1902, according to another embodiment. Referencecharacters in FIG. 19 refer to the same features as like-numberedreference characters in FIG. 16; for example, 1602 in FIGS. 16 and 1902in FIG. 19 both refer to an HE-SIG-B field, S1605A and S1905A both referto an encoding of a padded common field, and so on.

The process 1900 of FIG. 19 differs from the process 1600 of FIG. 16 inthat the encoded and rate matched padding bits 1926A and 1926B,respectively corresponding to the padding bits 1916A and padding bits1916B, are removed from the outputs 1920 and 1924 of the rate matchingprocesses 1907A and 1907B, respectively, before the outputs 1920 and1924 are concatenated and interleaved at S1909.

In an embodiment of the process 1900, the padding bits 1916A and 1916Bare respectively appended to the outputs of the encoding process at51905A and 51905B, instead of to the inputs of the encoding process at51905A and 51905B as is shown in FIG. 19.

The removal of the output bits corresponding to the filler bits 1916Aand 1916B prior to interleaving and modulation reduces the overheadincurred by the filler bits 1916A and 1916B, but maintains the samepuncturing pattern for each of a common field 1910 and one or moreper-STA information fields 1914, that is, for each information fieldcorresponding to a BCC block in the HE-SIG-B field 1902.

As in the process 1600, the puncturing pattern used in the process 1900is not dependent of the respective locations of the common field 1910and or the per-STA information fields 1914 within the HE-SIG-B field1602. Accordingly, each of the common field 1910 and the one or moreper-STA information fields 1914 will be rate-matched using an identicalpuncturing pattern and are each boundary aligned with rate-matchingunits of the transmission.

FIG. 20 illustrates a process 2000 for BCC rate-matching of a portion ofan HE-SIG-B field 2002, according to the embodiment of FIG. 19. Theprocessor may be performed by a device in a WLAN performing atransmission, such as an AP. In FIG. 20, the code-rate is 3/4, and therate-matching unit is therefore 3 bits, but embodiments are not limitedthereto.

Reference characters in FIG. 20 refer to the same features aslike-numbered reference characters in FIG. 17; for example, 1702 inFIGS. 16 and 2002 in FIG. 20 both refer to an HE-SIG-B field, S1705A andS2005A both refer to an encoding of a padded common field, and so on.

The process 2000 of FIG. 20 differs from the process 1700 of FIG. 17 inthat the encoded and rate matched padding bits 2026, corresponding tothe padding bits 2004-1-P, are removed from the first and secondpunctured encoded bits 2010-1 and 2010-2 before the first and secondpunctured encoded bits 2010-1 and 2010-2 are combined at 52013 to form apunctured encoded bit stream 2014. The punctured encoded bit stream 2014includes a first portion 2016-1 corresponding to the first field 2004-1,and a second portion 2016-2 corresponding to the second field 2004-2.

FIG. 21 illustrates a process 2100 for decoding a received HE-SIG-Bsignal 2102, according to an embodiment. The process 2100 is suitablefor use by a wireless device to decode a transmission performedaccording to the process 1900 of FIG. 19.

As S2103, the received HE-SIG-B signal 2102 is demodulated andequalized. The equalization may include phase tracking and compensation.The demodulation may output signals in the form of log-likelihood ratio(LLR) values.

At S2105, the demodulated and equalized received HE-SIG-B signal isde-interleaved in units of OFDM signals to generate a demodulatedreceived HE-SIG-B signal 2104. When the demodulation of S2103 outputssignals in the form of LLR values, the LLR values are de-interleaved inunits of OFDM symbols to generate a demodulated received HE-SIG-B signal2104. The demodulated received HE-SIG-B signal 2104 is sent for de-ratemapping at S2107.

At S2107, the demodulated received HE-SIG-B signal 2104 (in oneembodiment, the De-Interleaved LLR values) are divided into blocks, andpadding bits (or fill bits) 2212A, 2212B, and so on are added to make alength of each block equal to an integer multiple of the rate-matchingunit, if necessary. Each padded block is then de-rate-mapped. De-ratemapping includes inserting dummy bits to replace bits discarded during arate mapping performed at, for example, S1907A or S1907B of FIG. 19. Theordering of the values of the demodulated received HE-SIG-B signal 1804and the dummy bits is determined by the puncturing pattern used duringthe rate mapping.

At S2109, the de-rate-mapped BCC blocks are each decoded to produce acommon field 2110 and one or more per-STA information fields 2114. AViterbi algorithm may be used to perform the decoding.

At S2111, the CRC, BCC tail bits, and any padding added at S2107 areremoved from the common field 2110 and the one or more per-STAinformation fields 2114.

In an embodiment, some fields within an HE-SIG-B field may be encodedaccording to the process 1600 of FIG. 16, and other fields within theHE-SIG-B field may be encoded according to the process 1900 of FIG. 19.For example, in an embodiment, a common info field and all but a last ofper-STA information field of the HE-SIG-B field are encoded according tothe process 1900, and the last per-STA information field of the HE-SIG-Bfield is encoded using the process 1600.

When HE-SIG-B channels are repeated in frequency, such as in 80 MHz or160 MHz transmissions, the repeated received HE-SIG-B signals may bethrown away in the receiver or may be combined in the LLR domain, priorto decoding, for a maximum ratio combining effect, resulting in higherdecoding performance.

FIG. 22A illustrates an HE-SIG-B field 2200A including filler bits forrate-matching unit alignment, according to a first embodiment. TheHE-SIG-B field 2200A includes a common field 2202 and a user-specificinformation field 2204A. The user-specific information field 2204Aincludes one or more per-STA information fields (in the example shown,first, second, and third per-STA information fields 2206A-1, 2206A-2,and 2206A-3, respectively) and padding 2208. The padding 2208 is used tomake the HE-SIG-B field 2200A occupy a whole number of OFDM symbols.

Each of the per-STA information fields 2206A-1, 2206A-2, and 2206A-3includes control information for up to 2 stations: the first per-STAinformation field 2206A-1 includes first and second STA informations2216-1 and 2216-2, the second per-STA information field 2206A-2 includesthird and fourth STA informations 2216-3 and 2216-4, and the thirdper-STA information field 2206A-3 includes fifth STA information 2216-5.

The first to fifth STA informations 2216-1 to 2216-5 include controlinformation for first to fifth stations, respectively.

The first to third per-STA information fields 2206A-1, 2206A-2, and2206A-3 further include first to third CRC fields 2218-1 to 2218-3 andfirst to third tail bits 2220-1 to 2220-3.

The common field 2202 includes resource allocation (RU) signaling forvarious bandwidths and can contain up to 4 RU allocation subfields. Theexample of FIG. 22 shows an HE-SIG-B field that is one of two HE-SIG-Bfields in an 80 MHz PPDU, and as a result the common field 2202 includesfirst and second RU allocation fields 2210A and 2210B, whichrespectively include RU allocation information for first and second 20MHz bandwidths of the 80 MHz PPDU. The common field 2202 furtherincludes a CRC field 2212 and tail bits 2214.

Each of the common field 2202 and the per-STA information fields2206A-1, 2206A-2, and 2206A-3 are BCC blocks. Each of the common field2202 and the per-STA information fields 2206A-1, 2206A-2, and 2206A-3includes rate-matching filler bits 2222-1, 2222-2, 2222-3, and 2222-4,respectively, that include sufficient bits to make the length of therespective BCC blocks an integer multiple of the rate-matching unit forthe MCS being used to encode the HE-SIG-B field 2200A. If one or more ofthe common field 2202 and the per-STA information fields 2206A-1,2206A-2, and 2206A-3 have a length that is an integer multiple of therate-matching unit without padding, the respective padding bits may beomitted.

In the embodiment of FIG. 22A, the rate-matching filler bits 2222-1,2222-2, 2222-3, and 2222-4 are inserted after the tail bits of therespective BCC blocks, that is, the rate-matching filler bits 2222-1,2222-2, 2222-3, and 2222-4 are appended, if necessary, to the ends ofthe BCC block.

The values of the bits of the rate-matching filler bits 2222-1, 2222-2,2222-3, and 2222-4 can be 0, which aids the BCC encoder in maintainingan all-zero zero state at the end of the BCC block.

FIG. 22B illustrates an HE-SIG-B field 2200B including filler bits forrate-matching unit alignment, according to a second embodiment. TheHE-SIG-B field 2200B differs from the HE-SIG-B field 2200B of FIG. 22Ain the location of the rate-matching filler bits 2222-1, 2222-2, 2222-3,and 2222-4.

In the HE-SIG-B field 2200B, the rate-matching filler bits 2222-1,2222-2, 2222-3, and 2222-4 are inserted between the CRC-field and Tailbit fields of the BCC blocks. In the common field 2202, therate-matching filler bits 2222-1 is inserted between the CRC field 2212and tail bits 2214. In the per-STA information fields 2206A-1, 2206A-2,and 2206A-3, the rate-matching filler bits 2222-2, 2222-3, and 2222-4are inserted between the CRC fields 2218-1, 2218-2, and 2218-3 and thetail bits 2220-1, 2220-2, and 2220-3, respectively. The values of therate-matching filler bits can be 0.

In another embodiment, the rate-matching filler bits may be added to thefront of the information field or between the content of the informationfield and the CRC/Tail bits. In such an embodiment, the values of thefiller bit can be set to 1 or 0. In an embodiment, the rate-matchingfiller bits are set to 1 in order to generate more randomized signalsafter BCC encoding of the information fields.

In an embodiment, the rate-matching filler bits vary as a function of anMCS used to transmit an HE-SIG-B field. The MCS of the HE-SIG-B fieldmay be signaled in an HE SIG-A field. For example, in MCS 0, 1, and 3,(which uses 1/2 code-rate), no rate matching filler bits are required.For MCS 2, 4, 6, and 8 (which uses 3/4 code-rate), the common andper-STA information fields should have rate-matching filler bitsinserted, when necessary, to make that their lengths each divisible by 3(e.g. 0, 1, or 2 filler bits per field). For MCS 5 (which uses 2/3code-rate), the common and per-STA information field should haverate-matching filler bits inserted so that their lengths are eachdivisible by 2 (e.g. 0 or 1 filler bit per field). For MCS 7 and 9(which uses 5/6 code-rate), the common and per-STA information fieldshould have rate-matching filler bits inserted so that their lengths areeach divisible by 5 (e.g. 0, 1, 2, 3, or 4 filler bits per field).

In another embodiment, the filler bits can be design to be included ineach common field such that it supports rate-matching unit boundaryalignment of the information fields for all supported MCS of theHE-SIG-B field.

For example, if the HE-SIG-B field supports MCS indexes of 0 to 6, whichtogether use one of code-rates 1/2, 2/3, and 3/4, then when each of acommon field and one or more per-STA information fields of the HE-SIG-Bfield has a length that is an integer multiple of 6 bits (the leastcommon multiple of 1, 2, and 3), the common field and one or moreper-STA information fields will each be an integer number ofrate-matching units long for any of the supported MCS. From zero to fiverate-matching filler bits may inserted such that each common field andper-STA information field are an integer multiple of 6 bits long.

In another example, if the HE-SIG-B field supports MCS indexes of 0 to9, when the common field and per-STA information fields have a lengththat is an integer multiple of 30 bits (least common multiple of 1, 2,3, 5), the common field and one or more per-STA information fields willeach be an integer number of rate-matching units long for any of thesupported MCS. From 0 to 29 rate-matching filler bits are inserted suchthat each common field and per-STA information field are an integermultiple of 30 bits long.

Table 2 of FIG. 8 shows the number of data subcarriers per OFDM symbol,N_(SD), number of encoded bits per OFDM symbol, N_(CBPS), and number ofpayload bits (prior to encoding) per OFDM symbol, N_(DBPS), for eachconfigured MCS of an HE-SIG-B field. N_(RM) denote the rate-matchingunit for each MCS. Based on the information in Table 2, an equation canbe derived for computing the number of filler bits for the commoninformation field and each per-STA information field, and the number ofpadding bits to append to the HE-SIG-B field contents.

Let N_(COMMON) be the number of bits for the common information field(excluding Filler, CRC, and Tail bits). Let N_(STA-SPECIFIC) be thenumber of bits for a single per-STA information field. A per-STAinformation field consists of 1 or 2 station informations, filler,(possibly CRC), and BCC tail bits. Let N_(TAIL) be the number of tailbits for BCC, which is fixed at 6 bits. Let N_(CRC1) and N_(CRC2) be thenumber of CRC bits for the common field and per-STA information fields,respectively. Note that if that CRC and STA-ID of a per-STA informationfield are exclusive-or'd together, as described in some embodimentsabove, N_(CRC2) may be zero, because there may not be any explicit CRCbits added to the per-STA information fields. Let N_(STA,1) andN_(STA,2) be the number of per-STA information that needs to be conveyedin HE-SIG-B channels 1 and 2, respectively.

For the embodiment illustrated in FIGS. 16-18, a number of filler bitsfor a common field N_(FILL-COMMON), a first number of filler bitsN_(FILL1) for per-STA information fields having one station information,and a second number of filler bits N_(FILL2) for per-STA informationfields having two station informations may be computed as follows:N _(FILL-COMMON)=(N _(COMMON) +N _(CRC1) +N _(TAIL))mod N_(RM)  Equation 2N _(FILL2)=(2·N _(STA-SPECIFIC) +N _(CRC2) +N _(TAIL))mod N_(RM)  Equation 3N _(FILL1)=(N _(STA-SPECIFIC) +N _(CRC2) +N _(TAIL))mod N_(RM)  Equation 4

Then a number of HE-SIG-B field contents, N_(SIGB,k), for each ofHE-SIG-B channels 1 and 2, is computed for each HE-SIG-B channel k, k=1to 2:

$\begin{matrix}{N_{{SIGB},k} = {( {N_{COMMON} + N_{{CRC}\; 1} + N_{TAIL} + N_{{FILL} - {COMMON}}} ) + {\lfloor \frac{N_{{STA},k}}{2} \rfloor \cdot ( {{2 \cdot N_{{STA} - {SPECIFIC}}} + N_{{CRC}\; 2} + N_{TAIL} + N_{{FILL}\; 2}} )} + {( {N_{{STA},\; k}\mspace{14mu}{mod}\; 2} ) \cdot ( {N_{{STA} - {SPECIFIC}} + N_{{CRC}\; 2} + N_{TAIL} + N_{{FILL}\; 1}} )}}} & {{Equation}\mspace{14mu} 5}\end{matrix}$

Then the required number of OFDM symbols, N_(SYM,k), for each HE-SIG-Bchannel, is computed for each HE-SIG-B channel k, k=1 to 2:

$\begin{matrix}{N_{{SYM},k} = \lfloor \frac{N_{{SIG},k}}{N_{DBPS}} \rfloor} & {{Equation}\mspace{14mu} 6}\end{matrix}$

The HE-SIG-B channels must have the same number of OFDM symbols,therefore the final HE-SIG-B number of symbols, N_(SYM), is the maximumof the two:N _(SYM)=max(N _(SYM,1) ,N _(SYM,2))  Equation 7

Finally, a number of padding bits, N_(PAD,k), for each HE-SIG-B channelk, k=1 to 2, can be computed by:N _(PAD,k) =N _(DBPS) ·N _(SYM) −N _(SIGB,k)  Equation 8

For the embodiment illustrated in FIGS. 19-21, a number of filler bitsfor a common field N_(FILL-COMMON), a first number of filler bitsN_(FILL1) for per-STA information fields having one station information,and a second number of filler bits N_(FILL2) for per-STA informationfields having two station informations may be computed using Equations2, 4, and 3, respectively, above.

The number of encoded HE-SIG-B field contents, {circumflex over(N)}_(SIGB,k), for each HE-SIG-B channel k, k=1 to 2, is computed:

$\begin{matrix}{{\hat{N}}_{{SIGB},k} = {\lceil \frac{N_{COMMON} + N_{{CRC}\; 1} + N_{TAIL}}{r} \rceil + {\lfloor \frac{N_{{STA},k}}{2} \rfloor \cdot \lceil \frac{{2 \cdot N_{{STA} - {SPECIFIC}}} + N_{{CRC}\; 2} + N_{TAIL}}{R} \rceil} + {( {N_{{STA},\; k}\mspace{14mu}{mod}\; 2} ) \cdot \lceil \frac{N_{{STA} - {SPECIFIC}} + N_{{CRC}\; 2} + N_{TAIL}}{R} \rceil}}} & {{Equation}\mspace{14mu} 9}\end{matrix}$

Next the required number of OFDM symbols, N_(SYM,k), for each HE-SIG-Bchannel k, k=1 to 2, are computed:

$\begin{matrix}{{N_{{SYM},k} = {{\lceil \frac{{\hat{N}}_{{SIGB},k}}{N_{CBPS}} \rceil\mspace{14mu}{for}\mspace{14mu} k} = 1}},2} & {{Equation}\mspace{14mu} 10}\end{matrix}$

The HE-SIG-B channels 1 and 2 must have the same number of OFDM symbols,therefore the final HE-SIG-B number of symbols, N_(SYM), is the maximumof the two:N _(SYM)=max(N _(SYM,1) ,N _(SYM,2))  Equation 11

In a first embodiment, wherein the padding bits are added prior toencoding, the number of padding bits, N_(PAD,k), for each HE-SIG-Bchannel can be computed by:N _(PAD,k)=└(N _(CBPS) ·N _(SYM) −{circumflex over (N)} _(SIGB,k))·R┘for k=1,2  Equation 12

In a second embodiment, wherein padding bits are added after encoding(option 1 computes the padding bits prior to encoding), the number ofpadding bits, Ñ_(PAD,k), for each HE-SIG-B channel can be computed by:Ñ _(PAD,k) =N _(CBPS) ·N _(SYM) −{circumflex over (N)} _(SIGB,k) fork=1,2  Equation 13

Embodiments can reduce the HE-SIG-B field signaling overhead and enablea receiver to perform decoding, and in particular BCC rate-de-matching,efficiently.

The solutions provided herein have been described with reference to awireless LAN system; however, it should be understood that thesesolutions are also applicable to other network environments, such ascellular telecommunication networks, wired networks, etc.

The above explanation and figures are applied to an HE station, an HEframe, an HE PPDU, an HE-SIG field and the like of the IEEE 802.11axamendment, but they can also applied to a receiver, a frame, PPDU, a SIGfield, and the like of another future amendment of IEEE 802.11.

Embodiments of the present disclosure include electronic devicesconfigured to perform one or more of the operations described herein.However, embodiments are not limited thereto.

Embodiments of the present disclosure may further include systemsconfigured to operate using the processes described herein. The systemsmay include basic service sets (BSSs) such as the BSSs 100 of FIG. 1,but embodiments are not limited thereto.

Embodiments of the present disclosure may be implemented in the form ofprogram instructions executable through various computer means, such asa processor or microcontroller, and recorded in a non-transitorycomputer-readable medium. The non-transitory computer-readable mediummay include one or more of program instructions, data files, datastructures, and the like. The program instructions may be adapted toexecute the processes and to generate and decode the frames describedherein when executed on a device such as the wireless devices shown inFIG. 1.

In an embodiment, the non-transitory computer-readable medium mayinclude a read only memory (ROM), a random access memory (RAM), or aflash memory. In an embodiment, the non-transitory computer-readablemedium may include a magnetic, optical, or magneto-optical disc such asa hard disk drive, a floppy disc, a CD-ROM, and the like.

In some cases, an embodiment of the invention may be an apparatus (e.g.,an AP station, a non-AP station, or another network or computing device)that includes one or more hardware and software logic structure forperforming one or more of the operations described herein. For example,as described above, the apparatus may include a memory unit, whichstores instructions that may be executed by a hardware processorinstalled in the apparatus. The apparatus may also include one or moreother hardware or software elements, including a network interface, adisplay device, etc.

While this invention has been described in connection with what ispresently considered to be practical embodiments, embodiments are notlimited to the disclosed embodiments, but, on the contrary, may includevarious modifications and equivalent arrangements included within thespirit and scope of the appended claims. The order of operationsdescribed in a process is illustrative and some operations may bere-ordered. Further, two or more embodiments may be combined.

What is claimed is:
 1. A method performed by a wireless device, themethod comprising: generating, by the wireless device, a rate-matchedHigh Efficiency Signal B (HE-SIG-B) field by Block Convolution Code(BCC) encoding an HE-SIG-B field and rate-matching, according to apuncturing pattern, a BCC block of the encoded HE-SIG-B field;generating, by the wireless device, a Physical Layer Protocol Data Unit(PPDU) including the rate-matched HE-SIG-B field; and transmitting, bythe wireless device, the PPDU, wherein a total number N is a totalnumber of bits of the HE-SIG-B field that precede the BCC block, whereinthe total number N is greater than 0, and wherein the puncturing patterndepends on the total number N.
 2. The method of claim 1, wherein the BCCblock has a code-rate of K/M, K and M being positive integers greaterthan zero, so that K bits of the BCC block are encoded into M bits, andwherein the puncturing pattern depends on a remainder Z, the remainder Zbeing equal to the total number N modulo K.
 3. The method of claim 2,wherein the puncturing pattern is equal to a basic puncturing patternfor the code-rate K/M left cyclic-shifted by the remainder Z.
 4. Themethod of claim 3, wherein BCC encoding the BCC block includes:generating a first set of encoded bits using a first polynomial, andgenerating a second set of encoded bits using a second polynomial. 5.The method of claim 4, wherein the code-rate is 3/4, wherein the firstset of encoded bits includes a first plurality of consecutive three-bitsequences beginning at an earliest bit of the first set of encoded bits,wherein the second set of encoded bits includes a second plurality ofconsecutive three-bit sequences beginning at an earliest bit of thesecond set of encoded bits, and wherein rate-matching the BCC blockincludes: discarding a third bit of each of the first plurality ofconsecutive three-bit sequences and a second bit of each of the secondplurality of consecutive three-bit sequences when the remainder Z isequal to zero; discarding a second bit of each of the first plurality ofconsecutive three-bit sequences and a first bit of each of the secondplurality of consecutive three-bit sequences when the remainder Z isequal to one; and discarding a first bit of each of the first pluralityof consecutive three-bit sequences and a third bit of each of the secondplurality of consecutive three-bit sequences when the remainder Z isequal to two.
 6. The method of claim 4, wherein the code-rate is 2/3,wherein the second set of encoded bits includes a plurality ofconsecutive two-bit sequences beginning at an earliest bit of the secondset of encoded bits, and wherein rate-matching the BCC block includes:discarding a second bit of each of the plurality of consecutive two-bitsequences when the remainder Z is equal to zero; and discarding a firstbit of each of the plurality of consecutive two-bit sequences when theremainder Z is equal to one.
 7. The method of claim 4, wherein thecode-rate is 5/6, wherein the first set of encoded bits includes a firstplurality of consecutive five-bit sequences beginning at an earliest bitof the first set of encoded bits, wherein the second set of encoded bitsincludes a second plurality of consecutive five-bit sequences beginningat an earliest bit of the second set of encoded bits, and whereinrate-matching the BCC block includes: discarding third and fifth bits ofeach of the first plurality of consecutive five-bit sequences and secondand fourth bits of each of the second plurality of consecutive five-bitsequences when the remainder Z is equal to zero; discarding second andfourth bits of each of the first plurality of consecutive five-bitsequences and first and third bits of each of the second plurality ofconsecutive five-bit sequences when the remainder Z is equal to one;discarding first and third bits of each of the first plurality ofconsecutive five-bit sequences and second and fifth bits of each of thesecond plurality of consecutive five-bit sequences when the remainder Zis equal to two; discarding second and fifth bits of each of the firstplurality of consecutive five-bit sequences and first and fourth bits ofeach of the second plurality of consecutive five-bit sequences when theremainder Z is equal to three; and discarding first and fourth bits ofeach of the first plurality of consecutive five-bit sequences and thirdand fifth bits of each of the second plurality of consecutive five-bitsequences when the remainder Z is equal to four.
 8. The method of claim1, wherein the HE-SIG-B field includes a plurality of BCC blocks, andfurther comprising: BCC encoding the plurality of BCC blocks of theHE-SIG-B field as a single codeword.
 9. The method of claim 1, whereinthe HE-SIG-B field includes a plurality of BCC blocks, wherein aplurality of total numbers N are respective total numbers of bits of theHE-SIG-B field that respectively precede the respective BCC blocks ofthe plurality of BCC blocks; and further comprising: separatelyrate-matching the BCC blocks of the plurality of BCC blocks usingrespective puncturing patterns determined using the respective totalnumbers N.
 10. The method of claim 1, wherein the BCC block correspondsto a per-station (per-STA) information field, the per-STA informationfield including information for one or two stations.
 11. A methodperformed by a wireless device, the method comprising: receiving, by thewireless device, a Physical Layer Protocol Data Unit (PPDU) including arate-matched High Efficiency Signal B (HE-SIG-B) field; and generating,by the wireless device, a decoded HE-SIG-B field by de-rate-matching anddecoding the rate-matched HE-SIG-B field, the rate-matched HE-SIG-Bfield including a rate-matched Block Convolution Code (BCC) block,wherein generating the decoded HE-SIG-B field includes de-rate-matchingthe rate-matched BCC block according to a puncturing pattern dependingon a total number N, wherein the total number N is a total number ofbits of the decoded HE-SIG-B field corresponding to bits of therate-matched HE-SIG-B field that preceded the BCC block, and wherein thetotal number N is greater than
 0. 12. The method of claim 11, whereinthe BCC block has a code-rate of K/M, K and M being positive integersgreater than zero, so that K bits of the BCC block are encoded into Mbits, and wherein the puncturing pattern depends on a remainder Z, theremainder Z being equal to the total number N modulo K.
 13. The methodof claim 12, wherein the puncturing pattern is equal to a basicpuncturing pattern for the code-rate K/M left cyclic-shifted by theremainder Z.
 14. The method of claim 13, wherein the code-rate is 3/4,and wherein de-rate-matching the encoded BCC block includes: for each ofa plurality of consecutive four-value sequences {x1, x2, x3, x4} in theencoded BCC block: generating a first three-value sequence {x1, x3, D}and a second three-value sequence {x2, D, x4} when the remainder Z isequal to zero; generating the first three-value sequence {x1, D, x3} andthe second three-value sequence {D, x2, x4} when the remainder Z isequal to one; and generating the first three-value sequence {D, x2, x4}and the second three-value sequence {x1, x3, D} when the remainder Z isequal to two, wherein the plurality of consecutive four-value sequencesbegins at an earliest value of the encoded BCC block, and wherein D is apredetermined dummy value.
 15. The method of claim 13, wherein thecode-rate is 2/3, and wherein de-rate-matching the encoded BCC blockincludes: for each of a plurality of consecutive three-value sequence{x1, x2, x3} in the encoded BCC block: generating a first two-valuesequence {x1, x3} and a second two-value sequence {x2, D} when theremainder Z is equal to zero; and generating the first two-valuesequence {x1, x2} and the second two-value sequence {D, x3} when theremainder Z is equal to one, wherein the plurality of consecutivethree-value sequences begins at an earliest value of the encoded BCCblock, and wherein D is a predetermined dummy value.
 16. The method ofclaim 13, wherein the code-rate is 5/6, and wherein de-rate-matching theencoded BCC block includes: for each of a plurality of consecutivesix-value sequence {x1, x2, x3, x4, x5, x6} in the encoded BCC block:generating a first five-value sequence {x1, x3, D, x6, D} and a secondfive-value sequence {x2, D, x4, D, x6} when the remainder Z is equal tozero; generating the first five-value sequence {x1, D, x3, D, x5} andthe second five-value sequence {D, x2, D, x4, x6} when the remainder Zis equal to one; generating the first five-value sequence {D, x2, D, x4,x6} and the second five-value sequence {x1, D, x3, x5, D} when theremainder Z is equal to two; generating the first five-value sequence{x1, D, x3, x5, D} and the second five-value sequence {D, x2, x4, D, x6)when the remainder Z is equal to three; and generating the firstfive-value sequence {D, x2, x4, D, x6} and the second five-valuesequence {x1, x3, D, x5, D) when the remainder Z is equal to four,wherein the plurality of consecutive six-value sequences begins at anearliest value of the encoded BCC block, and wherein D is apredetermined dummy value.
 17. The method of claim 11, wherein theHE-SIG-B field includes a plurality of BCC blocks, wherein the encodedHE-SIG-B field includes a plurality of portions respectivelycorresponding to the plurality of BCC blocks, and further comprising:de-rate-matching the plurality of portions as a single codeword.
 18. Themethod of claim 11, wherein the HE-SIG-B field includes a plurality ofBCC blocks, wherein the encoded HE-SIG-B field includes a plurality ofportions respectively corresponding to the plurality of BCC blocks,wherein a plurality of total numbers N are respective total numbers ofbits of the HE-SIG-B field that respectively precede the respective BCCblocks of the plurality of BCC blocks, and further comprising:separately de-rate-matching the portions of the encoded HE-SIG-B fieldaccording to respective puncturing patterns determined according to therespective total numbers N.
 19. The method of claim 11, wherein the BCCblock corresponds to a per-station (per-STA) information field, theper-STA information field including information for one or two stations.